Tayari Jones has won the Women's Prize for Fiction for her story about a family torn apart by the US judicial system.
An American Marriage, which was selected by Oprah Winfrey for her book club and praised by Barack Obama, focuses on Celestial and Roy, a successful African-American couple in Atlanta whose marriage is tested when the husband is sentenced to 12 years in prison for rape, a crime he didn't commit. Chair of the judges Kate Williams described the novel as "a story of love, loss and intimacy that shines a light on today's America".
"It's an incredible examination of America and American life, focusing on the intimacy of a marriage but on a huge political canvas," said Williams. "The prose is luminous, striking and utterly moving. [The novel illustrates] how hard it is, even when you're on the outside and are free, how you're not really free when you have someone in prison."
Accepting the £30,000 (Dh140,000) award, Jones said: "I am thrilled and honoured. I wasn’t expecting to win. The shortlist was so strong and I was honoured to be among them but I had no idea whether I would win. I didn’t write a speech!"
Jones, a professor of English at Emory University in Atlanta, beat five other finalists to the prize, including Booker Prize winners Pat Barker and Anna Burns. An American Marriage is Jones's fourth novel, but the first to be published in the UK.
Speaking at the awards ceremony in London, Jones asked readers to remember "the millions of people who are incarcerated around the world". She explained that the novel had its origins in an exchange she overheard between a man and a woman at a shopping mall. "They were so in love and they were in trouble," Jones told AP. "And she said, 'Roy, you wouldn't have waited on me for seven years.' And he said, 'This wouldn't have happened to you in the first place.'
"I thought they were both right. When I have a situation where both characters are right yet they disagree, that's a story I can spend some years wrestling with."
Asked whether she hoped US President Donald Trump would read An American Marriage, as his predecessor in the White House did, Jones said: "I'm delighted that Obama read my book and I'm delighted that I had a president in my time that read books and recommended them, who cared about the past and history, who used it to guide us to the future. I have no real hope or desire that the current occupant of the White House will read my book."
Oprah Winfrey has already bought the film rights to An American Marriage and Jones says she is due to see a screenplay "any second now".